Infants born at a very low birth weight are at greater risk for experiencing memory and attention problems during adulthood than infants born at a low to normal weight.

“While we know babies born severely preterm generally achieve lower cognitive test scores, this is one of the first studies to look at how severely low birth weight impacts executive functioning, such as attention and visual memory, when these babies become young adults,” said study author professor Katri Räikkönen, PhD, of the University of Helsinki in Finland.

For the Helsinki Study, researchers evaluated 103 adults who had been born at a very low birth weight (less than 3.3 pounds) as well as 105 adults who weighed over 3.3 pounds at the time of birth.

The participants (between the ages of 21 and 30) were given tests that measured the following thinking skills: vocabulary, ability to understand words, memory and IQ.

Researchers discovered that adult participants with very low birth weights scored lower or performed more slowly in general intelligence, executive functioning and attention and visual memory compared to adults with a low to normal birth weight.

Specifically, participants with a very low birth weight scored an average 8.4 points (0.57 standard deviation units) lower on the full IQ test and 0.30-0.54 standard deviation units lower on the executive functioning and attention and memory tests.

Furthermore, participants with a very low birth weight were more likely to have received remedial education in school, but no differences were found in their self-reported academic performance.

“Interestingly, average school grades and the number of years of education completed were not affected by low birth weight in our study,” said Räikkönen.

“However, our research underscores the importance of a baby’s full development in the womb.”